[PATCH v1 01/21] accel/tcg: Change interrupt/exception handling to remove implied BQL

[Robert Foley]

This change removes the implied BQL from the cpu_handle_interrupt,
and cpu_handle_exception paths. This BQL acquire is being pushed
down into the per arch implementation.

Signed-off-by: Robert Foley <robert.foley@linaro.org>
---
 accel/tcg/cpu-exec.c | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/accel/tcg/cpu-exec.c b/accel/tcg/cpu-exec.c
index 80d0e649b2..8e2bfd97a1 100644
--- a/accel/tcg/cpu-exec.c
+++ b/accel/tcg/cpu-exec.c
@@ -517,9 +517,7 @@ static inline bool cpu_handle_exception(CPUState *cpu, int 
*ret)
 #else
         if (replay_exception()) {
             CPUClass *cc = CPU_GET_CLASS(cpu);
-            qemu_mutex_lock_iothread();
             cc->do_interrupt(cpu);
-            qemu_mutex_unlock_iothread();
             cpu->exception_index = -1;
 
             if (unlikely(cpu->singlestep_enabled)) {
@@ -558,7 +556,7 @@ static inline bool cpu_handle_interrupt(CPUState *cpu,
     if (unlikely(cpu_interrupt_request(cpu))) {
         int interrupt_request;
 
-        qemu_mutex_lock_iothread();
+        cpu_mutex_lock(cpu);
         interrupt_request = cpu_interrupt_request(cpu);
         if (unlikely(cpu->singlestep_enabled & SSTEP_NOIRQ)) {
             /* Mask out external interrupts for this step. */
@@ -567,7 +565,7 @@ static inline bool cpu_handle_interrupt(CPUState *cpu,
         if (interrupt_request & CPU_INTERRUPT_DEBUG) {
             cpu_reset_interrupt(cpu, CPU_INTERRUPT_DEBUG);
             cpu->exception_index = EXCP_DEBUG;
-            qemu_mutex_unlock_iothread();
+            cpu_mutex_unlock(cpu);
             return true;
         }
         if (replay_mode == REPLAY_MODE_PLAY && !replay_has_interrupt()) {
@@ -577,13 +575,15 @@ static inline bool cpu_handle_interrupt(CPUState *cpu,
             cpu_reset_interrupt(cpu, CPU_INTERRUPT_HALT);
             cpu_halted_set(cpu, 1);
             cpu->exception_index = EXCP_HLT;
-            qemu_mutex_unlock_iothread();
+            cpu_mutex_unlock(cpu);
             return true;
         }
 #if defined(TARGET_I386)
         else if (interrupt_request & CPU_INTERRUPT_INIT) {
             X86CPU *x86_cpu = X86_CPU(cpu);
             CPUArchState *env = &x86_cpu->env;
+            cpu_mutex_unlock(cpu);
+            qemu_mutex_lock_iothread();
             replay_interrupt();
             cpu_svm_check_intercept_param(env, SVM_EXIT_INIT, 0, 0);
             do_cpu_init(x86_cpu);
@@ -595,7 +595,7 @@ static inline bool cpu_handle_interrupt(CPUState *cpu,
         else if (interrupt_request & CPU_INTERRUPT_RESET) {
             replay_interrupt();
             cpu_reset(cpu);
-            qemu_mutex_unlock_iothread();
+            cpu_mutex_unlock(cpu);
             return true;
         }
 #endif
@@ -604,7 +604,9 @@ static inline bool cpu_handle_interrupt(CPUState *cpu,
            True when it is, and we should restart on a new TB,
            and via longjmp via cpu_loop_exit.  */
         else {
+            cpu_mutex_unlock(cpu);
             if (cc->cpu_exec_interrupt(cpu, interrupt_request)) {
+                cpu_mutex_lock(cpu);
                 replay_interrupt();
                 /*
                  * After processing the interrupt, ensure an EXCP_DEBUG is
@@ -614,6 +616,8 @@ static inline bool cpu_handle_interrupt(CPUState *cpu,
                 cpu->exception_index =
                     (cpu->singlestep_enabled ? EXCP_DEBUG : -1);
                 *last_tb = NULL;
+            } else {
+                cpu_mutex_lock(cpu);
             }
             /* The target hook may have updated the 'cpu->interrupt_request';
              * reload the 'interrupt_request' value */
@@ -627,7 +631,7 @@ static inline bool cpu_handle_interrupt(CPUState *cpu,
         }
 
         /* If we exit via cpu_loop_exit/longjmp it is reset in cpu_exec */
-        qemu_mutex_unlock_iothread();
+        cpu_mutex_unlock(cpu);
     }
 
     /* Finally, check if we need to exit to the main loop.  */
@@ -691,7 +695,6 @@ static inline void cpu_loop_exec_tb(CPUState *cpu, 
TranslationBlock *tb,
     }
 #endif
 }
-
 /* main execution loop */
 
 int cpu_exec(CPUState *cpu)
-- 
2.17.1